BAEL-1402 code for the article: Try-with-resources in Kotlin

This commit is contained in:
Alessio Stalla 2018-01-14 22:50:55 +01:00
parent c174946f85
commit a758fd9cef
2 changed files with 72 additions and 0 deletions

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@ -44,6 +44,11 @@
<artifactId>kotlin-stdlib</artifactId> <artifactId>kotlin-stdlib</artifactId>
<version>${kotlin-stdlib.version}</version> <version>${kotlin-stdlib.version}</version>
</dependency> </dependency>
<dependency>
<groupId>org.jetbrains.kotlin</groupId>
<artifactId>kotlin-stdlib-jre8</artifactId>
<version>${kotlin-stdlib.version}</version>
</dependency>
<dependency> <dependency>
<groupId>org.jetbrains.kotlin</groupId> <groupId>org.jetbrains.kotlin</groupId>
<artifactId>kotlin-test-junit</artifactId> <artifactId>kotlin-test-junit</artifactId>

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@ -0,0 +1,67 @@
package com.baeldung.kotlin
import org.junit.Test
import java.beans.ExceptionListener
import java.beans.XMLEncoder
import java.io.*
import java.lang.Exception
import kotlin.test.assertEquals
import kotlin.test.assertTrue
import kotlin.test.fail
class UseTest {
@Test
fun givenCloseable_whenUseIsCalled_thenItIsClosed() {
val stringWriter = StringWriter()
val writer = BufferedWriter(stringWriter) //Using a BufferedWriter because after close() it throws.
writer.use {
assertEquals(writer, it)
it.write("something")
}
try {
writer.write("something else")
fail("write() should have thrown an exception because the writer is closed.")
} catch (e: IOException) {
//Ok
}
assertEquals("something", stringWriter.toString())
}
@Test
fun givenAutoCloseable_whenUseIsCalled_thenItIsClosed() {
val baos = ByteArrayOutputStream()
val encoder = XMLEncoder(PrintStream(baos)) //XMLEncoder is AutoCloseable but not Closeable.
//Here, we use a PrintStream because after close() it throws.
encoder.exceptionListener = ThrowingExceptionListener()
encoder.use {
assertEquals(encoder, it)
it.writeObject("something")
}
try {
encoder.writeObject("something else")
encoder.flush()
fail("write() should have thrown an exception because the encoder is closed.")
} catch (e: IOException) {
//Ok
}
}
@Test
fun whenSimpleFormIsUsed_thenItWorks() {
StringWriter().use { it.write("something") }
}
}
class ThrowingExceptionListener : ExceptionListener {
override fun exceptionThrown(e: Exception?) {
if(e != null) {
throw e
}
}
}